1. Field of the Invention
The present invention generally relates to time reference management in audio and video systems.
2. Background Art
Accurate playback of audio/visual media can be problematic for the audio and video subsystems, such as those used in conventional computer systems. For example, when digital video discs (DVDs) are played on laptop computers, audio and pixel clocks, within the lap top's audio and video subsystems, can drift apart. This drift can cause the movie's audio and video tracks to lose their synchronization, creating artifacts in the display.
Drift reduction techniques used in the conventional computer systems typically drop or repeat frames to compensate for this drift between the audio and video tracks. However, dropping or repeating frames can be quite noticeable to a user, and is therefore less than optimal.
These conventional computer systems typically use a crystal based timing reference signal to provide a global clock reference. The use of a global clock reference, however, does little to eliminate the problem of drift noted above.
What is needed, therefore, are methods and systems to more efficiently synchronize the audio and video tracks of audio/visual media to substantially eliminate or reduce the occurrence of drift.